Darmstadt clinched promotion to the Bundesliga with a 1-0 win over St Pauli.
Tobias Kempe scored the only goal of the game at Stadion Bollenfalltor, finding the back of the net with a long-range free-kick in the 71st minute.
The result means Darmstadt finish the season in second place, five points behind Bundesliga 2 champions Ingolstadt.
Dirk Schuster's side will now be back in the top tier of German football for the first time since the 1981-82 season.
Since then the club has gone through tough times on and off the field, including fighting off the threat of bankruptcy as they came close to going out of business.
However, in the last two seasons, Darmstadt have secured back-to-back promotions, meaning they will return to the Bundesliga for the first time in 33 years.
Darmstadt's delight meant disappointment for Karlsruher, who missed out on second place by one point despite a 2-0 home win over 1860 Munich.
